Soil

Question 1

diffrence between soil and rock

Answer 1

separate soil using water only

Question 2

hard granular

Answer 2

grains of hard rock materials espically silicates

Question 3

soft granular

Answer 3

coral, shell, skeletal, fragments and volcanic ash

Question 4

clay materials

Answer 4

small crystalline material, plate shapred particles

plate-like particles, negative charges on the outside, interacts with water, sweels and shrinks, gives soil plasticity

Question 5

plant resdidue

Answer 5

peat, vegetation, organic matter

Question 6

Equation for porosity

Answer 6

Vv / Vt

Vt = total volume of solid, water, sand 
Vv = water and air

Question 7

equation for void ratio

Answer 7

Vv / Vs

Vs = solids 
Vv = water and air

Question 8

Denisty

Answer 8

mass / volume

Question 9

strength of soil

Answer 9

compression = good
tension = not so goos
shear = varies

2 shear strength parameters
- friction and cohension

Question 10

fiction

Answer 10

effect on strength increasing with depth

Question 11

cohension

Answer 11

soil moisture, plasticity, transient

Question 12

soil and compaction

Answer 12

if you compact the soil when it improves it for construction
( density control = drives the air out)

Question 13

what is rammed earth made up of

Answer 13

70% sand
30% clay
- check the denisty and water content

Question 14

Advantage of earth construction

Answer 14

low cost
easy to build
easy to repair
environmetally sustainable
thermall mass

Question 15

disadvantage of earth construction

Answer 15

water
weathering
erosion
material availbility
shape / form
earthquake resistance

Question 16

environmental impact of earth construction

Answer 16

low fossil fuel demand
low transport demand
highly recyclability and durable
good thermal mass

Question 17

advantage of rammed earth

Answer 17

thermal mass
residue and noise control
strength
durability
low thermal
fireproofing

Question 18

rammed earth construction

Answer 18

roof overhang - keeps it dry
concrete beam to support floor slabs - stable connection
start walls above grade - splash protection
optional side drain
a solid foundation - rammed earth walls are heavy

Question 19

what is rammed earth made environmentally?

Answer 19

70-80% sand = fine gravel
20-30% clay = not too plastic
5-10% cement = optional
compacted well

Question 20

vernacular and residue methods

Answer 20

vernacular = loess, adobe, troglodites
innovation = rammed, stabilised earth

Question 21

what is adobe

Answer 21

loess good band material
silt and clay size (10-25%)
high void ratio, cemented and collapsible

wetted collapsed loess materials
reformed and dried
bricks and plaster

Question 22

how to make adobe

Answer 22

make adobe right soil
wet it, mix it, dry it
build bricks, walls and plaster

Question 23

what is cob

Answer 23

lump and rounded mass

Question 24

what is soil made off?

Answer 24

1-2 parts clay
1 part silt
2-3 parts sand
3-4 gravel
plus some straw (3-5%)

layers rammed together by hand making thick walls

Question 25

Advantages of cob/ soil

Answer 25

load-bearing
simple
cheap
no tools
durable
strong
fire-resistant
insulation